Automatic journal lift apparatus for grinding mills

ABSTRACT

Apparatus for lifting journals of heavy rotary equipment away from metal to metal contact with underlying bearing portions and simultaneously lubricating the journals prior to imparting rotary movement to the rotary equipment.

United States Patent lnventor Clifford E. Lovold Two Harbors, Minn. Appl. No. 21,577 Filed Mar. 23, 1970 Patented Dec. 7, 1971 Assignee Reserve Mining Company Silver Bay, Minn.

AUTOMATIC JOURNAL LIFT APPARATUS FOR GRINDING MILLS 6 Claims, 3 Drawing Figs.

11.8. CI 184/63, 24l/D1G. 20, 308/122 lnt. Cl F160: 33/66 Field of Search 184/6, 6 A,

[56] References Cited UNITED STATES PATENTS 3,374,863 3/1968 Kozlowski et a1 184/6 A 3,350,018 10/1967 Harris et a1. 308/122 X 3,076,523 2/1963 Fuller et al.. 308/122 X 2.661.813 12/1953 Kennedy l84/6A Primary E.taminerManuel A. Antonakas AnorneyMerchant & Gould ABSTRACT: Apparatus for lifting journals of heavy rotary equipment away from metal to metal contact with underlying bearing portions and simultaneously lubricating the journals prior to imparting rotary movement to the rotary equipment.

PATENTED DEC 7 IHYI SHEET 1 [IF 2 INVENTOR. CLIFFORD E LOVOLD A T TORNEYS PATENTED DEC 7 I97! SHEET 2 UF 2 INVENTOR. Gun-0R0 E LOVOLD BY /Wp W ATTORNEYS AUTOMATIC JOURNAL LIFT APPARATUS FOR GRINDING MILLS BACKGROUND OF THE INVENTION This invention relates particularly to the field of rotary cylindrical mills for reducing ores and like materials, such as rod or ball mills. These include cylindrical housings having aligned axial journals at their opposite ends disposed on generally horizontal axes and supported in generally semicylindrical bearings. The mills are of large size and extremely heavy. Hence, when rotation of a mill is stopped, the weight thereof breaks the film of lubricating oil between each journal and the underlying bearing, resulting in metal-to-metal contact between each journal and its cooperating bearing. Then, when it is desired to again initiate operation of the mill, oil or like lubricant must be forced between each bearing and journal under sufficient pressure to provide a lubricant film therebetween, before rotation can be imparted to the mill without undue strain on the drive motor therefor.

Heretofore, manually operated pumps as well as motordriven pumps have been used to initially supply lubricant to the bottom of the journals and lift them out of metal-to-metal contact with their underlying bearings. Depending upon the size and type of mill, pressures of approximately 2,000 to 7,500 pounds per square inch are required to lift and initially lubricate the journals. Pumps of such pressure ratings, driven by electric motors, heretofore used, have been very expensive and have required attention of the operator both in turning the same on when starting the mill, and turning the pump off when running speed of the mill is attained. Manually operated pumps, while being much less costly, have the disadvantage of requiring a pair of workers in starting a mill, one to operate the pump and another to operate the control panel to start the mill, while the first worker continues to operate the manual pump. If only one operator is used, he first manually operates the pump to generate the desired pressure, then moves to the control panel to start the mill. Often, before the mill reaches running speed, the oil pressure under the journals decreases to a point where the film of lubricant is broken. This condition places such a load on the mill drive motor that it does not reach its synchronous or running speed, and the pumping operation must be repeated, or an additional operator used to operate the pump during the starting operation.

SUMMARY OF THE INVENTION The apparatus of this invention, once manually initiated by the closing of a switch, is automatic in its operation. The apparatus comprises a pair of high-pressure lubricant pumps each having a discharge connected by a conduit to a different one of a pair of journal hearings in underlying relation to each journal. Each pump is driven by an individual drive motor, such as a pneumatic reciprocatory piston equipped cylinder, or air motor, obtainable at relatively low cost. The mill drive motor is controlled by means including a pair of pressure operated switches each operatively associated with a different one of the pumps, the mill drive motor being energized only when a predetermined pressure of lubricant under each journal, sufficient to raise the same from contact with the underlying portion of the bearing, is reached. The apparatus includes other control devices for automatically deenergizing the pump operating motors when the mill drive motor reaches synchronous or full operating speed.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation of a mill having the apparatus of this invention applied thereto, some parts being broken away and some parts being shown in section;

FIG. 2 is an enlarged transverse section taken substantially on the line 22 of FIG. I; and

FIG. 3 is a wiring diagram.

A cylindrical grinding mill is shown fragmentarily in FIG. l as comprising a generally horizontally disposed cylindrical wall l, and opposite end walls 2 that are formed to provide axially outwardly projecting hollow trunnions or journals 3 that are rotatably mounted in bearings 4 which in turn are mounted on supporting pillars or pedestals 5. A gear 6 encompasses the cylindrical wall 1 adjacent one of the end walls 2, and is bolted or otherwise rigidly secured to the cylindrical wall I, and has meshing engagement with a drive pinion 7 rigidly mounted on the drive shaft 8 of a suitable electric drive motor indicated at 9 in FIG. 3. The motor 9 is preferably of the squirrel cage or synchronous variety usually employed for the turning of heavy loads. It will be appreciated that the mill, which may be a ball or rod mill is of large size and of great weight, the same being generally used in the mining industry for reducing ore.

The mill illustrated in FIG. I is of the type disclosed in Us. Letters Pat. No. 3,401,893, issued to .l. A. Reynolds, and assigned to the assignee company of this invention. As disclosed in the Reynolds patent, a liner I0 is bolted to one of the end walls 2, one of the trunnions 3, namely the infeed trunnion 3 being provided with an infeed liner II that is generally frustoconical in shape and provided with flanges I2 and 13 that engage the inner surface of the adjacent journal 3. The liner 11 is provided with vanes 14 for directing slurry, comprising fragmented ore and liquid, such as water, to the interior of the mill, the slurry being fed to the interior of the liner 11 through a suitable conduit, indicated at 15. A discharge conduit or chute 16 is suitably mounted in the trunnion 3 at the opposite end of the mill, see FIG. I.

The bearings 4 are substantially identical, only one of them being shown in detail. Each bearing 4 comprises upper and lower bearing housing sections 17 and 18 respectively, bolted together, as indicated at 19. Each upper section 17 cooperates with its respective journal 3 to define a reservoir 20 or lubricant, such as oil, each lower housing section 18 having mounted therein a generally semicylindrical bearing element 21 having a liner 22 of suitable bearing material that engages the outer surface of its adjacent journal 3.

It will be appreciated that ball mills of the type above described, used in the mining industry, are extremely heavy, a typical mill being in the neighborhood of IO feet in diameter and 16 feet in length, so that the load placed upon the bearing elements 21 and their liners 22 by the journals 3 is very great. As a matter of fact, when rotation of a mill is stopped, the pressure of the journals 3 downwardly against the bearing elements 21 is sufficient to break the film of lubricant therebetween so that, at the bottom portion of each journal 3, metal-to-metal contact exists between the journal 3 and underlying portion of the liner 22 of the bearing element 21. Hence, in many installations, the bearings 4 are provided with lubricant conduits 23 that extend from the outside of the bearings 4 and terminate at their inner ends at the bottom portions of the bearing elements 21 and liners 22, as indicated at 24 in FIG. 2. The conduits 23 are adapted to be connected to one or more high-pressure lubricant pumps having sufiicient pressure capacity to introduce lubricant to the bottom portion of the journals 3 against the extreme downward pressure exerted by the journals 3 against their respective bearing elements 21, and sufficiently to raise the journals 3 out of metalto-metal contact with their respective bearing liners 22.

The automatic journal lifting apparatus of this invention comprises a pair of high-pressure piston pumps 25 that are each mounted in a different one of a pair of oil reservoirs 26, each of the pumps 25 having an outlet fitting 27 to which is connected a high-pressure conduit 28 that extends to a conduit 23 in a respective one of the bearings 4. Check valves 29 and manual control valves 30 are disclosed in the high-pressure conduits 28, see FIG. I. The reservoirs 26 are connected to an oil supply line 31 by branch conduit means, indicated at 32, the supply line 31 being used to maintain a supply of oil or other liquid lubricant in the oil reservoirs of the bearings 4. The pumps are operated by individual air operated motors 33 having air inlet fittings 34 that are connected to an air supply conduit 35 by means of branch conduits 36, the supply conduit 35 being adapted to be connected to a source of air under pressure, not shown. A valve 37 is interposed in the air supply line 35 is controlled by a solenoid 38. The pumps 25 and their respective air pressure operated motors 33 are preferably of the type manufactured and sold by the Lincoln Engineering Company, a division of the McNeil Machine & Engineering Company of St. Louis, Missouri, the pumps and motors being unitary structures and identified as the manufacturers series D. Inasmuch as the pumps 25 and motors 33, in and of themselves, do not constitute the instant invention, further detailed showing and description hereof is omitted, in the interest of brevity. It should suffice to state that the pumps 35 and motors 33 are of the reciprocatory piston type, the pistons of each pump 25 being rigidly connected to the pistons of their respective air motors 33 and being of substantially less piston area than the pistons of their respective motors 33. This arrangement provides for a substantial pressure differential between the input to each motor 33 and output of each pump 25.

Operation of the mill drive motor 9 is controlled in part by a pair of pressure-responsive switches 39 and 40 that are connected in series in a control circuit including a lead 41 in which is interposed a master switch 42 and the coil 43 of a relay 44. The opposite ends of the lead 41 are connected to power conductors 45 and 46 of a three-conductor power line including a third conductor 47. The relay 44 further includes normally open switches 48, 49 and 50 interposed in respective ones of power leads 51, 52 and 53 that extend from the power conductors 45, 46 and 47 respectively to the motor 9,. A holding circuit for the motor control relay 44 includes a portion of lead 51, the relay switch 48, and a holding lead 54 connected to the switch 48 and to lead 41 between the relay coil 43 and the pressure-responsive switch 39.

The pressure-responsive control switches 39 and 40 are each disposed in a different one of a pair of housings 55, and are normally open. The switches 39 and 40 are closed by respective switch actuators 56 and 57 contained within a respective one of housings 55, and connected to respective ones of the pressure conduits 28 by branch conduits 58.

The solenoid 38 is connected in a circuit which includes the master switch 42, a portion of lead 41, and a lead 59, in which is interposed a normally open switch 60 of a relay 61, the relay 61 including a relay coil 62. The relay coil 62 is disposed in a circuit which includes master switch 42, a portion of lead 41, and a lead 63 connected at one end to the lead 41 and at its other end to the power conductor 45. A normally closed switch 64 is interposed in the lead 63 in series with the relay coil 62, and is adapted to be opened by suitable means, such as a conventional governor 65 operatively associated with the mill drive motor 9 as indicated by the dotted line 66 in FIG. 3.

OPERATION With the mill at rest, and the switch 42 open, the solenoid operated valve 37 is closed, the switches 39, 40 and 60 are open as are the switches 48, 49 and 50, and the governor operated switch 64 is closed. Closing of the switch 42 causes a circuit to be completed through the relay coil 62, closing the switch 60 and completing a circuit through the solenoid 38 to open the valve 37. Air under pressure is admitted to the air motors 33 through the open valve 37, where upon the pumps 25 operate to introduce lubricant under pressure through the conduits 23 to the bottom portions of the journals 3. The switch actuators 56 and 57 are so set or adjusted that, when sufficient pressure is generated under the trunnions or journals 3 to lift the same out of metal-to-metal contact with their respective bearing liners 22, the switches 39 and 40 are closed by their respective actuators 56 and 57, closing a circuit through the coil 43 of the relay 44. The relay 44 thus energized, the switches 48-50 thereof are closed to energize mill drive motor 9. In view of the fact that switches 39 and 40 are disposed in a series arrangement, the relay 44 will not be energized to start the motor 9 until sufficient pressure has been generated under both journals 3 to lift the same away from metal-to-metal contact with their underlying bearings. As the motor 9 accelerates to its synchronous or full operating speed, the air motors 33 continue to operate their respective pumps 25 to supply lubricant to the bottom portions of the journals 3. When the motor 9 reaches its predetermined operating or synchronous speed, the governor 65 opens the switch 64 to deenergize the relay 61, opening the switch 60 and deenergizing the solenoid 38. At full running speed, lubricant is carried by the journals 3 into the spaces between the journals 3 and their underlying bearings from their respective reservoirs 20, eliminating the necessity for operation of the pumps 25 at normal operating speed of the mill. When the pumps 25 are shut off, reducing pressure of lubricant in the conduits 28, the switches 39 and 40 are opened by the actuators 56 and 57 respectively. The holding lead 54 cooperates with portions of leads 41 and 51 and switches 42 and 48 to maintain the relay coil 43 energized, thus keeping the motor 9 operating until the master switch 42 is opened.

From the above it will be seen that, once the switch 42 is closed, energization of the pumps 25 to effect raising of the journals 3 and lubricating the bottom portions thereof, staning of the motor 9 and shutting off operation of the pumps 25 after the mill driving motor 9 has reached its full operating speed, is entirely automatic, requiring no further attention by the operator.

While I have shown and described a preferred embodiment of my automatic journal lifting apparatus, it will be understood that the same is capable of modification without departure from the spirit and scope of the invention, as defined in the claims.

What is claimed is:

1. Apparatus for lifting a pair of axially spaced generally horizontally disposed journals of a rotary structure from respective underlying bearings therefore, said rotary structure having rotary drive means, said apparatus comprising:

a. a pair of high-pressure liquid lubricant pumps having discharge openings;

b. conduits connecting said pump discharge openings each to a different one of the journal hearings to conduct liquid lubricant under high pressure to said journals at the bottoms thereof;

c. motor means drivingly connected to said pumps;

d. and control means including a pair of fluid pressure operated control elements each operatively connected to a different one of said conduits and a rotary speed responsive control element operatively connected to said rotary drive means, said fluid-pressure operated control elements being responsive to a predetermined rise in pressure of lubricant under only both of said journals to energize said rotary drive means, said rotary speed responsive control element being operatively responsive thereafter to rotation of said rotary drive means at a predetennined speed to deenergize said motor means.

2. The apparatus according to claim 1 in which said motor means comprises a pair of motors each drivingly connected to a different one of said pumps.

3. The apparatus according to claim 1 in which said rotary drive means includes an electric motor, said control means comprising a control circuit; said fluid-pressure operated control elements comprising switches, said switches being connected in series in said control circuit, whereby said predetermined pressure is required under both journals to energize said electric motor.

4. The apparatus according to claim 3 in which said control means includes a holding circuit for said electric motor and operative to maintain the electric motor energized after deenergization of said pair of motors.

5. The apparatus according 0 claim 1 in which said motor means comprises a pair of fluid operated motors each drivingly connected to a different one of said lubricant pumps, characterized by conduit means for connecting said fluid operated motors to a source of fluid under pressure, said control means comprising a valve in said conduit means controlling delivery of fluid to said fluid operated motors, and a control circuit including a solenoid for operating said valve.

6. The apparatus according to claim 1 in which said rotary drive means includes an electric motor, said motor means comprising a pair of fluid-pressure operated motors each drivingly connected to a different one of said lubricant pumps, 

1. Apparatus for lifting a pair of axially spaced generally horizontally disposed journals of a rotary structure from respective underlying bearings therefore, said rotary structure having rotary drive means, said apparatus comprising: a. a pair of high-pressure liquid lubricant pumps having discharge openings; b. conduits connecting said pump discharge openings each to a different one of the journal bearings to conduct liquid lubricant under high pressure to said journals at the bottoms thereof; c. motor means drivingly connected to said pumps; d. and control means including a pair of fluid pressure operated control elements each operatively connected to a different one of said conduits and a rotary speed responsive control element operatively connected to said rotaRy drive means, said fluidpressure operated control elements being responsive to a predetermined rise in pressure of lubricant under only both of said journals to energize said rotary drive means, said rotary speed responsive control element being operatively responsive thereafter to rotation of said rotary drive means at a predetermined speed to deenergize said motor means.
 2. The apparatus according to claim 1 in which said motor means comprises a pair of motors each drivingly connected to a different one of said pumps.
 3. The apparatus according to claim 1 in which said rotary drive means includes an electric motor, said control means comprising a control circuit; said fluid-pressure operated control elements comprising switches, said switches being connected in series in said control circuit, whereby said predetermined pressure is required under both journals to energize said electric motor.
 4. The apparatus according to claim 3 in which said control means includes a holding circuit for said electric motor and operative to maintain the electric motor energized after deenergization of said pair of motors.
 5. The apparatus according to claim 1 in which said motor means comprises a pair of fluid operated motors each drivingly connected to a different one of said lubricant pumps, characterized by conduit means for connecting said fluid operated motors to a source of fluid under pressure, said control means comprising a valve in said conduit means controlling delivery of fluid to said fluid operated motors, and a control circuit including a solenoid for operating said valve.
 6. The apparatus according to claim 1 in which said rotary drive means includes an electric motor, said motor means comprising a pair of fluid-pressure operated motors each drivingly connected to a different one of said lubricant pumps, said fluid-pressure operated control elements comprising a pair of switches connected in series, characterized by conduit means for connecting each of said fluid-pressure operated motors to a source of fluid under pressure, and a valve in said conduit means, said control means comprising electrical circuitry including: a. a valve operating solenoid for said valve; b. said switches; c. and a holding circuit for said electric motor for maintaining said electric motor energized after de-energization of said fluid-pressure operated motors. 